This invention relates to a liquid filter and, more particularly, to a liquid filter including an openable filter housing, an unfiltered-liquid inlet, a clean-liquid outlet, and first and second filter elements. The first filter element is arranged in the filter housing and is designed essentially in the shape of a hollow cylinder. The liquid flow travels through the first filter element from its exterior to its interior.
Hicks, German Patent No. DE 825,537, discloses a filter which is suitable for filtering liquids. This known filter has essentially two filter elements. The liquid to be cleaned flows into a concentric space formed between the two filter elements. The liquid then flows from the concentric space through the two filter elements. This leaves the liquid in both the core area of the filter and at an outer circumferential area of the filter. The known filter is designed as an edge filter, in which case two different edge shapes may be selected.
It is a disadvantage of the known filter that the cleaned liquid emerges from the filter element on both the inside as well as on the outside of the element, thus making it difficult to guide the two liquid flows together. Naturally, it is also possible to reverse the flow direction. In this case, the cleaned liquid will flow out between the two filter elements. However, problems are then presented in the feeding of the unfiltered liquid.